Heat transfer device with functions of power generation

ABSTRACT

Provided is a heat transfer device which has a function of generating power through vibration of capillary grooves having a thin piezoelectric film deposited thereon, in addition to a heat transfer function of discharging heat transferred from a heating element to the outside.

TECHNICAL FIELD

The present invention relates to a heat transfer device capable ofgenerating power, and more specifically, to a heat transfer device whichnot only has a heat transfer function of discharging heat transferredfrom a heating element to the outside, but also has a function ofgenerating power through vibration of capillary grooves having apiezoelectric thin film deposited thereon.

BACKGROUND ART

Recently, as computers and various electronic apparatuses are becomingreduced in size, the internal structure thereof is being compactlyintegrated. Therefore, the temperature of semiconductor chips mayincrease due to heat generated from the inside of the electronicapparatuses. In this case, the performance of the semiconductor chipsmay be degraded, or the lifespan thereof may be reduced.

To solve such an internal heat problem, a method of attaching a heatsink to a heating element has been conventionally used to cool down theheating element. However, when an electronic apparatus includes aplurality of heating elements for discharging a large amount of heat fora unit time, it is difficult to cool down the heat generated from theinside of the electronic apparatus with only the heat sink. Therefore,recently, a heat transfer device using a heat pipe has been frequentlyapplied. In particular, a heat transfer device using a small heat pipeis mainly used in notebook PCs and mobile phones, whose internal spaceis significantly reduced due to the miniaturization and integration.

The heat pipe is a passive type which has an excellent heat transfercharacteristic, does not generate noise, and does not require separatepower. The heat pipe can effectively transfer heat using latent heat forvaporization of a working fluid, even when there is a small temperaturedifference.

However, it is not preferable that the heat transfer device having onlythe cooling function is separately provided inside the electronicapparatus whose internal space is significantly reduced due to theminiaturization and integration. That is, to effectively use the narrowinternal space of a small-sized electronic apparatus, a heat transferdevice may be implemented to perform another function as well as theheat transfer function.

The present inventors have found that when a piezoelectric thin film isdeposited on surfaces of capillary grooves in a heat pipe, anelectromotive force is generated from the piezoelectric thin film as thecapillary grooves vibrate in a side-to-side or front and back directiondue to a phase change of the working fluid.

DISCLOSURE OF INVENTION Technical Problem

In order to solve the foregoing and/or other problems, it is anobjective of the present invention to provide a heat transfer devicewhich can not only transfer heat, but can also generate power.

Technical Solution

According to an aspect of the present invention, a heat transfer devicecomprises a vaporization unit including multi-channel capillary grooveswhich vaporize a working fluid through heat transferred from an externalheating element so as to generate vapor; and a condensation unit thatcondenses the vapor of the working fluid vaporized by the vaporizationunit and then returns the condensed liquid to the vaporization unit. Themulti-channel capillary grooves have a piezoelectric thin film depositedthereon, and vibrate due to the vapor of the vaporized working fluidsuch that power is generated from the multi-channel capillary grooves.

As the vapor of the vaporized working fluid slides and flows among themulti-channel capillary grooves, the multi-channel capillary grooveshaving the piezoelectric thin film deposited thereon may vibrate in aside-to-side or front and back direction. Accordingly, power isgenerated from the multi-channel capillary grooves.

Lower portions of the multi-channel capillary grooves may be connectedto a wall surface of the vaporization unit, and upper portions of themulti-channel capillary grooves may be formed in a cantilever shape suchthat the ends thereof can freely move. The working fluid may besaturated and uniformly distributed among the multi-channel capillarygrooves due to the capillary action of the multi-channel capillarygrooves.

The heat transfer device may further comprise a post-shaped bridge thatis formed between the vaporization unit and the condensation unit so asto prevent compression. The bridge may be used as a liquid flow paththrough which the condensed liquid returns to the vaporization unit.

Advantageous Effects

The heat transfer device according to the present invention has afunction of generating power through the vibration of the capillarygrooves having a thin piezoelectric film deposited thereon, in additionto the heat transfer function of discharging the heat transferred fromthe heating element to the outside. Therefore, since the heat transferdevice can provide a heat transfer function as a cooling element and apower supply function as a power generator to small-sized electronicapparatuses, its effective value is expected to increase.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are schematic views of a heat transfer device capable ofgenerating power according to the present invention.

FIG. 2 is a diagram for explaining heat transfer operation of the heattransfer device according to the present invention.

FIGS. 3A and 3B are diagrams for explaining power generation operationof the heat transfer device according to the present invention.

FIGS. 4A and 4B are diagrams showing a state in which bridges are formedin the heat transfer device according to the present invention.

MODE FOR THE INVENTION

Hereinafter, an example embodiment of the present invention will bedescribed in detail with reference to the accompanying drawings.However, it will be appreciated by those skilled in the art that variouschanges may be made to these example embodiments, and the scope of thepresent invention is not limited to the example embodiments. The exampleembodiments are provided to more clearly explain the present inventionto those skilled in the art.

FIGS. 1A and 1B are schematic views of a heat transfer device capable ofgenerating power according to the present invention. FIG. 2 is a diagramfor explaining heat transfer operation of the heat transfer deviceaccording to the present invention.

Referring to FIGS. 1A and 1B, the heat transfer device 100 capable ofgenerating power according to the present invention has an airtightstructure of which the inner space is maintained in a vacuum state.

A working fluid 103 is injected into the heat transfer device 100 havingsuch an airtight structure, and heat transfer between a vaporizationunit 110 and a condensation unit 130 is performed by a phase change ofthe injected working fluid 103.

The vaporization unit 110 coming in contact with a heating element (notshown) has multi-channel capillary grooves 101. Through the capillaryaction of the capillary grooves 101, the working fluid 103 can beuniformly distributed among the capillary grooves 101 without a separatepower source.

Lower portions of the capillary grooves 101 are connected to the wallsurface of the vaporization unit 110, and upper portions of thecapillary grooves 101 are formed in a cantilever shape such that theends thereof can move freely.

The working fluid 103 may be liquid which has been initially injected tothe heat transfer device 100 or liquid which has been condensed in thecondensation unit 130 and returned. The working fluid 103 is alwayssaturated among the capillary grooves 101, and the phase change of theworking fluid 103 is repeated depending on the amount of heat applied tothe vaporization unit 110.

Referring to FIG. 2, the working fluid 103 which has been saturatedamong the capillary grooves 101 is phase-changed by the heat applied tothe vaporization unit 110 so as to vaporize. The vapor V_(F) of theworking fluid 103 transfers latent heat H_(L) to the wall surface of thecondensation unit 130 and is then condensed. Further, the working fluidC_(F) condensed in the condensation unit 130 returns to the vaporizationunit 110 along the wall surface of the heat transfer device 100.

As the vaporization and the condensation are repeatedly performed, theheat transferred from the heating element (not shown) is discharged tothe outside.

The heat transfer device 100 constructed in such a manner can rapidlytransfer heat, generated from one side, to the other side. Therefore,the heat transfer device 100 may be used as a heat dissipating devicewhich effectively dissipates hot spots of a heat source. Further, theheat transfer device 100 of the present invention can be operated in theanti-gravity direction in which a heat source is positioned at the upperend thereof, and can be operated regardless of a tilted angle thereof.

Meanwhile, the heat transfer device 100 according to the presentinvention has a power generation function, in addition to theabove-described heat transfer function. The power generation functionwill be described below in detail.

FIGS. 3A and 3B are diagrams for explaining the power generationoperation of the heat transfer device according to the presentinvention.

Referring to FIGS. 3A and 3B, when the working fluid 130 saturated amongthe capillary grooves 101 is vaporized by the heat applied to thevaporization unit 110, vapor V_(F) of the working fluid 103 slides andflows among the capillary grooves 101 due to a pressure difference. Atthis time, the capillary grooves 101 vibrate in a side-to-side or frontand back direction due to the flowing of the vapor V_(F) of thevaporized working fluid 103.

That is, since the lower portions of the capillary grooves 101 areconnected to the wall surface of the vaporization unit 110 and the upperportions of the capillary grooves 101 are formed in a cantilever shapesuch that the ends of the capillary grooves 101 can freely move, thecapillary grooves 101 vibrate due to the vapor V_(F) of the workingfluid 103 sliding and flowing among the capillary grooves 101.

The capillary grooves 101 have a piezoelectric thin film 101 a depositedthereon. Accordingly, an electromotive force is generated from thepiezoelectric thin film 101 a by the vibration of the capillary grooves101. As a result, power can be generated.

Each of the capillary grooves 101 is connected to an electrode pattern Efor transferring the power generated by the piezoelectric thin film 101a. The electrode pattern E may be formed through a method of filling avia hole with a metallic material, the via hole passing through the wallof the vaporization unit 110. The electrode pattern E may be formedthrough another method.

The electromotive force generated by the piezoelectric thin film 101 adeposited on the surface of each of the capillary grooves 101 is low.However, since the plurality of capillary grooves 101 are formed in theheat transfer device 100, the overall power which is generated from theplurality of capillary grooves 101 and then collected by the electrodepatterns E is sufficiently high.

As long as the heat transfer by the phase change is continued, thevibration of the capillary grooves 101 is continuously performed, andeach of the capillary grooves 101 operates independently. Further, theshape and size of the capillary grooves 101 is determined depending onthe number and intensity of vibrations.

Meanwhile, since the inside of the heat transfer device 100 ismaintained in a vacuum state, compression of the vaporization unit 110and the condensation unit 130 may occur in a middle portion of the heattransfer device 100, depending on the area and wall thickness of theheat transfer device 100.

In the present invention, a bridge is formed in the heat transfer device100 so as to prevent the compression of the vaporization unit 110 andthe condensation unit 130. The bridge will be described in more detailwith reference to FIGS. 4A and 4B.

FIGS. 4A and 4B are diagrams showing a state where bridges 105 areformed in the heat transfer device 100 according to the presentinvention.

Referring to FIGS. 4A and 4B, the bridges 105 are formed in the heattransfer device 100 according to the present invention such that thevaporization unit 110 and the condensation unit 130 are spaced apredetermined distance from each other. The number, shape, and size ofthe bridges 105 may differ depending on the area and structure of theheat transfer device 100.

The bridge 105 can not only prevent the compression of the vaporizationunit 110 and the condensation unit 130, but may also serve as a liquidflow path through which the working fluid 103 condensed in thecondensation unit 130 returns to the vaporization unit 110.

In the heat transfer device 100 according to the present invention, theheat generated from the vaporization unit 110 by the phase change of theworking fluid 103 can be effectively transferred to the condensationunit 130. Further, as the capillary grooves 101 having the piezoelectricthin film 101 a deposited thereon vibrate in a side-to-side or front andback direction, power can be generated.

While the present invention has been shown and described in connectionwith exemplary embodiments thereof, it will be apparent to those skilledin the art that modifications and variations can be made withoutdeparting from the spirit and scope of the invention as defined by theappended claims.

1. A heat transfer device comprising: a vaporization unit includingmulti-channel capillary grooves which vaporize a working fluid throughheat transferred from an external heating element so as to generatevapor; and a condensation unit that condenses the vapor of the workingfluid vaporized by the vaporization unit and then returns the condensedliquid to the vaporization unit, wherein the multi-channel capillarygrooves have a piezoelectric thin film deposited thereon, and vibratedue to the vapor of the vaporized working fluid such that power isgenerated from the multi-channel capillary grooves.
 2. The heat transferdevice according to claim 1, wherein as the vapor of the vaporizedworking fluid slides and flows among the multi-channel capillarygrooves, the multi-channel capillary grooves having the piezoelectricthin film deposited thereon vibrate in a side-to-side or front and backdirection.
 3. The heat transfer device according to claim 1, whereinlower portions of the multi-channel capillary grooves are connected to awall surface of the vaporization unit, and upper portions of themulti-channel capillary grooves are formed in a cantilever shape suchthat the ends thereof can freely move.
 4. The heat transfer deviceaccording to claim 1, wherein the working fluid is saturated anduniformly distributed among the multi-channel capillary grooves due tothe capillary action of the multi-channel capillary grooves.
 5. The heattransfer device according to claim 1, wherein the heat transferred fromthe heating element by a phase change caused by the vaporization andcondensation of the working fluid is discharged through the condensationunit to the outside.
 6. The heat transfer device according to claim 1further comprising: a post-shaped bridge that is formed between thevaporization unit and the condensation unit so as to preventcompression.
 7. The heat transfer device according to claim 6, whereinthe bridge is used as a liquid flow path through which the condensedliquid returns to the vaporization unit.